TITLE	Continuing variation in colony morphology and fungicide sensitivity in Phytophthora cinnamomi following exposure to chloroneb
AUTHOR	Xia Bo Zheng Department of Plant Pathology, Beaumont Agricultural Research Center, University of Hawaii at Manoa, Hilo, Hawaii 96720, U. S. A. Wen-Hsiung Ko Department of Plant Pathology, Beaumont Agricultural Research Center, University of Hawaii at Manoa, Hilo, Hawaii 96720, U. S. A.
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ABSTRACT	A homothallic isolate of Phytophthora cinnamomi grown on agar medium containing fungicide chloroneb, produced fast growing resistant sectors within 3 weeks. The colony of a fungicide-resistant mutant, which was similar to the original flat (F) type, gave rise to single zoospore cultures consisting of a new cottony (C) type resistant to chloroneb and the F type either resistant or sensitive to chloroneb. The F type was continuously segregated from the C type in three successive zoospore generations. Although the chloroneb-sensitive F type revertants were stable, they produced more resistant sectors in a shorter time than did wild type when exposed again to chloroneb. Single zoospore cultures obtained from these resistant sectors were C type resistant to chloroneb and F type either resistant or sensitive to chloroneb. Both C and F type cultures resistant to chloroneb were unstable and segregated in successive zoospore generations in a fashion similar to that described above. The majority of zoospores (89 to 99%) produced by both C and F types were uninucleate.
KEYWORD	Chloroneb; Colony morphology; Fungicide sensitivity; Phytophthora cinnamomi; Variation;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 38 Number 3 July 1997, page 177-182, 6 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China